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ICT Applications
Security has always ben an overriding concern of human kind. For many organisation, information plays a very important role in running business. Therefore, it becomes necessary to safeguard information from reaching the illegal hands. When data takes the shapes of digital form, a different security procedure is required. This branch of security is called computer security.

Information technology has also some loopholes associated with it, like the possibility of stealing of vital information and intentionally implanting destructive or malicious programs on the other's computer system. The motive behind such activities is to show down the pace of an organisation and harm it economically. We shall discuss now about these malicious programs which are often called virus, worms, Trojan horse, logic bomb, spyware and os on.


Virus is a program which has been written to interfere with the normal functioning of the computer. It does this by clogging the memory of the system by making copies of itself or it may destory critical information used by other computer prgrams.

There are three main types of viruses: Boot sector viruses which infect the boot sector in the hard disk and affect the partition table, file viruses attach executable files. The commonly infected files are those with COM or EXE extensions. The third, system viruses infect specific system files such as Computer viruses can be grouped into Time Bomb, Trojan Horse, Worm etc. Time Bomb will start on a particular date, at a particular time. The computer will loose its ability to function properly.

The virus known as Trojan Horse will enter into a computer through an e-mail or free programs that have been down loaded from the internet and casue plenty of damage. Viruses known as Worms are constructed to infiltrate on the legitimate data processing programs and alter or destroy the data. Worm programs often use network connections to spread from one computer system to another system, thus, worms attach system that are linked through communication lines.

Protecting computer system using antivirus software

In case the virus is present, it becomes our duty to use some anti-virus software for preventing virus attacks in future. Anti-virus software falls into two categories: Scanners and integrity checkers.

A scanner is a program that will detect the virus by checking the files on the disk, the boot sector of the disk and programs in the memory by looking for the signature of the virus. The signature is a piece of program code that is unique to the virus. It is very necessary to update regularly the virus scanner that you have bought. This is essential because new viruses are constantly appearing.

Integrity checkers work using simple checksums or complicated algorithms or cryptographic checksums which check if a file

has been modified. It may be boring for you to check for virus every time you run the system. But you should not worry. Help is at hand with HomeGuard a unique device which once fitted to the computer automatically scans in the background for viruses. If there are viruses found in the system, HomeGuard will clean it up automatically without even having to press a key.

Precautions to be taken against viruses

  • Install a memory-resident program in RAM that will detect and warn if a virus is present.
  • Do not allow hardware engineers or sales persons to put a write enabled floppy into your computer uless they can guarantee that it is not infected.
  • Backup copies of all programs and data files should be kept.
  • Backup copies of programs should be held as read-only disks to prevent infection. At least 2 copies of the backup must be kept. Never boot your machine with a floppy from an unknown source.
  • Always write-protect your disk when you use it in another machine.
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ICT Applications